Die casting machine



Sept. 28, 1937. w. A. PARKER 2,094,079

y DIE CASTING MACHINE Filed oct. 6, 1934 33 f5 ma f5 f 5 -J fr 60 Hasi a INVENTOR.

' ATTORNEYS.

Patented Sept. 23, i937 Unit-TED STATES rAreN'r ori-*ice 2 Claim.

The present invention is designed to improve die casting machines and has particular reference to the manner ofclosing a 1d opening the die from a rotating driving means. With such a, mechanism it is possible to speed up the operation to a point that is nearly sufcient to chill the casting, open and discharge the mold, close and re-charge it. In'carrying out the invention a mechanism is preferably utilized which has no lost motion and which retains a continuous connection between the actuated'mold member and the rotating driving means and at the same time holds the mold positively Iin closed position during the chilling dwell of the mechanism. Features and details of the invention will appear more fully from the specification and claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing as follows:-

Fig. 1 shows a side elevation of the machine, partly in section.

Fig. 2 a section on the line 2-2 in Fig; 1.

Fig. 3 an enlarged view of the mold charging tube.

Fig. 4 a schematic view of the driving mechanism.

Fig. 5 ax section of the mold with the parts in closed'position.

Fig. 6 ase'ation on the line 6 6 in Fig. 5.

I marks the machine frame and Z legs supporting the frame. 7

A heating chamber 3 is provided ,with a burner 4, the burner being adapted to heat the molten metal rceptacle 5.n A charging cylinder t is supported by the receptacle and communicates with the receptacle through a port l., A plunger 8 operates in the cylinder, closing the port 'l in its downward "stroke so as to force themolten metal to the mold. A piston rod 9 extends from a plunger 8 to a piston I0. The piston I0 operates in an air cylinder I I. The piston has an extension I2 which extends into an inlet socket I3. Air is admitted to .the socket I3 by an inlet passage I4 extending from a. four-way valve I5. The valve has an'inlet passage I6 and has a valve plug I5a4, provided with two ports I1 which may, be brought alternately to the supply opening I4 connecting the same with the inlet I6, or with a discharge opening Ila. A connection I8 also extends to the valve I5 and leads to the lower end of the cylinder,II. This passage is also alternately connected bythe portsv I1 with the inlet passage I6 and the discharge passage Ila so thatas the valve is operated in proper'timing with relation to the other operations of the machine 4the frame I. Guide rods 28 extend beyond the by the mechanism hereinafter described the piston Ill is forced downwardly carrying with it the `plunger 8 and expelling a charge for the mold.

Atvthe proper interval the piston 8' is returned* with an initial suction action in its return move- 5 ment to facilitate the separationof the molten metal from the chilled metal of the mold and to uncover the port so ,as to permit an iniiow of molten metal. In the initial movement of the piston, the piston is retarded'by the extension i2 which restricts the incoming air so that the fllling of the 'air above the piston I0 is comparatively slow. This is desirable' in that the plunger does not violently expel the molten metalfrom the port I and gives a gradual start to the flow in the passage. A communicatingl port I9 extends from the lower end of the cylinder 6 up to the ycharging tube 20. 'I'he charging tube is fixed on the walls of the receptable at the discharge end of the port I9. The charging tube has a restriction 2i formed by the taper 22 which has its smaller end at' the restriction. This charging tube is arranged in an opening 23a in a mold supporting plate 23. A mold member 24 as shown has a mold cavity 25 and has a seat 24a adapted to seat on a seat 20a at the end of the charging tube. 'I'his connection permits of the ready charging of the mold. The mold member is provided with va chilling of the metal in the on'e end of the tube which metal 1s joined with the casting in the 40 mold cavity and the molten metal at the opposite end of the tube .is maintained in liquid state so that there is a ready separation, or backward movement of the molten metal at the completion of the casting operation. The taper passage of the tube 20 permits of the ready withdrawal of any `chilled metal that may extend from the casting into the'tube 20 and the inlet passage 25a of the mold-member is also tapered so as cross member 38a and into a rear pressure head 3| to which they are secured. An upper guide rod 29 is secured to and extends between the supporting plate 23 and the'head 3|. 4A reciprocating head 32 has bearings 33 which are slidingly mounted on the rods 28 and29. A toggle lever has members 34 and 35 pivotally'connected by pins 36. The forward end of the lever is pivotally connected at 31 with the reciprocating head 32. The rear member 35 is pivotally connected with the head 3| bya pin 38. A link 39 is connected by a pin 40 with the lever 34 adjacent to the pivotal connection at 36. The link is connected by a crank pin-4| with a crank 42. The crank 42 is fixed on a drive shaft 43. As indicated in Fig. 2, the toggle lever mechanism and crank are duplicated at each side of the machine, there being a crank at each endof the shaft 43. A worm gear 45 is xed on the shaft 43 and meshes with a worm 46. The worm is arranged on a worm shaft 41 and the shaft 41 is journaled in bearings 48 in the case 38. A driving pulley 49 is xed on the worm shaft and is driven from a t belt 50 from a pulley 5 I. The pulley 5| is fixed on v alinement.

' @a rotor shaft 52 of a motor 53.

'Through' this mechanism it will readily be seen that the crank is rotated and through its rotation reciprocates the link 39 swinging the toggle lever so as to open and close the mold. This toggle lever mechanism is brought to a position to close thevmold with the members 34 and 35 in substantial alinement. As indicated in Fig. 4, the crank is at the points a and-b when the parts`34 and 35 are in exact They are brought from slightly below that point in the travel of the crank represented at c. In actual operation the mold is -maintained in closed position from the point d to the point e, the spring of the included mechanism permitting the very slight variation in this interval. ln other words, while there is a continuous motion of the crank and while the toggle lever in its straightened position positively holds the molds under pressure and in closed position, a dwell in this closed position is accomplished by making the closed position in the part of thecrank travel where the movement from thecrank to the toggle levers and the movement of the toggle levers results in very little variation in the straight line arrangement of the toggle levers. Two'important factors enter into this result. By making the throw center of the crank (the throw center being the points in the travel of the crank where the reciprocating parts actuated l by the crank reverse) the more remote from the bers past alignment during the dwell portion of.

the throw of the crank the maximum divergence from alignment of the members is reduced. Thus a.V sixple, powerful driving connection is provided, comparatively fast duringv the opening and closing movements and with a dwell of sufficient length over a sufllcient period to procure the chilling of the `casting in the mold.

A movable member 54 of the mold has comple-l mentary mold parts completing the m'old with the cavity 25. 'I'his is provided withlwater cooling chambers 55 connected with a source of cooling liquid (not shown). The movable mold member is provided with a socket 56a which, with the mold closed, is directly opposite the charging passage 25a. 'I'his socket is connected by a lead 56 which connects the charging passage with the mold cavity. The socket' 56a has its walls shaped tov so engage the metal of the plug formed in the socket as to assist in withdrawing the casting from the stationarymold member. The mold member 54 is connected by straps, or plates 51 with a block 58 secured on the head 32 so that the mold member 54 reciprocates .with the head. A knock-out block 59 is slidingly mountedin the space between the member 54 and the block 58 on pins 60 which extend from thel member 54 to the block 58. Knock-out pins 6| and 62 extend from the knock-out block 59 through the mold member into position to engage the casting and discharge it from the mold. One of these pins 62 operates on the end of the plug formed in the-socket 56a. Push rods 63 are sliding mounted in perforations 64 in the head 32 and extend from the knock-out block 59. An abutment 65 is secured on the rod 29 .preferably adjustable by means of a securing screw 66. A thrust pin 61 extends from the knock-out block 59 through the mold member- 54 and is positioned to engage the face of the mold member 24 as the head 32 4with the mold member 54 is advanced. l

The molding operation i's as follows: The movable` member 54 is moved forward, closing the mold. With ,this forward movement, the pin 61 engages the mold member 24 and arrests the knock-out block 59 so as to retract the knockoutA pins 6| and 6 2 and bring them back to the faces of the molding surfaces. After the mold is charged and the metal chilled the member 54 is retracted opening the mold and in this rearward movement the push rods- 63 come into engagement with the abutment 65, thus arresting the knock-.out block 59 prior t'o the completion of the rearward movement of the mold member. With the continued movement hf the mold member the push-out pins 6| and 62 are projected through the mold vmember 54, thus disengaging the casting from the mold after which the operation of yclosing-the mold is repeated.

The air on the cylinder is automatically con--l trolled. A rock arm 68 is connected with' the valve plug |5a. A rod 69 connects the arm 68 witha bell crank lever 19 pivotally mounted on a pin 1| in the frame. A rod 12 extends from the bell crank lever to a rock ,arm 13. The rock arm is mounted on a pin 14 mounted on ,the gear case 30. Rock arms 15 and 16 are xed with the rock arm 13 and provided with rollers 11 at their ends. A cam 18 is arranged on the end of the vcrank 42 and the rollers 11 are in the path o f the cam 18 as the crank is rotated. As the mold is 4 closed the crank reaches the arm 15 and throws through the connecting mechanism the valve plug |5a to connect the upper end of the cylinder with the air supply.` The immediate downward movement of the piston and with it the plunger 8 chargesA the mold. After the mold is charged and at the completion of the dwell the cam 18 reaches the roller on the arm 16 and reverses the valve A|5 'so as to exhaust the upper end o! the cylinder and connect the lower end of the cylinder withV the air supply. The plunger l is then withdrawn and this withdraws the molten metal making the-break somewhere in the charging tube 28, the exact position of the break depending somewhat on the speed at\which the machine They plunger in'its v be .exerted vthrough the inertia of the aoeaove is run and the consequent extension 4of the chilling in the `tube-passage from the mold member 2li. return movement, as before stated, exerts initially a suction eiect on the molten metal in the port i9 and this aids in the prompt return movement of the molten metal from the point of parting with the chilled metal. This suction eiect is broken when the plunger passes theport '1. This'action is repeated with each cycleof the machine.

The piston i is considerably larger than the plunger 8` so that there isaJ very decided pressure diiierential. This may be made as much as desired depending on the available'air pressure for yoperating the piston and the proper pressure to on the molten metal in the mold. This pressure is increased by the fact that after the extension l2 leaves the socket i3 the air'ow on the piston is rapid and there is a very great acceleration of the piston so that it reaches the point where the mold is 4iilled at a very considerable velocity and this gives' to the metal as it lls the mold an added and nal pressure shock plunger and piston. In this wasr the mold isfilled rapidly and .with a very high final pressure.

It will be noted in the present structure that the mold has a xed member and a movable memberand that the knock-out action on the formed casting is accomplished through a single reciprocating mechanism. Thus the 'operating mechanism is very much simplified.

What I claim. asI new is:

1. In a die casting machine, a mold opening and closing mechanism comprising a reciprocating mold member; a continuously rotating driving crank provided with a crank pinya driving connection between the moldmember'ancl the as the crank passes l connection between mold member and crank including a link journaled on the crank pin with a bearing maintaining the axis of the bearing constant with the axis of the crank pin and a toggle joint to the link is connected, the toggle joint being connected to the mold member, said link and toggle jointvcommunicating the throw of the crank to the mold member and relatedto open the mold as the crank passes its ,throw center the more nearly adjacent tothe joint and to close the mold its throw centerlthe more remote from the joint andA With the members of the joint in-approximate alignment, providing a casting chilling dwell at the closed position of the member. y A

2. In a die casting machine, a mold opening and closing mechanism comprising a reciprocating mold member; ing crank provided a continuously rotating driv- With a crank pin; a driving the mold member and the crankincluding -a link journaled on the crank pin With a bearing. maintaining the axis of the bearing'constant with the axis of the crank pin and a toggle joint to which the opposite end of the link is connected, saidlink and toggle joint communicating the throw of the crank to the related to open the mold, as the crank passes its throw center the more nearly adjacent to the joint and to close the mold asA the crank passes its throw center the more remote from the joint and with the members of the joint in approximate alignment, providing a casting chilling dwell at the closed position of the member, the members of the joint being carried past alignment as center in closing the mold.

W. A. .PARKER.

the crank passes its throw which the opposite end of 

